Still little known, the impact of social isolation on health, especially heart health, is far from negligible. Recent studies show that its damage can be compared to that of well-established risk factors such as obesity, physical inactivity and even smoking. Loneliness is dangerous for health.
When we talk about chronic disease prevention, we usually think of the importance of quitting smoking, eating a plant-rich diet, exercising regularly and maintaining a normal body weight.
These lifestyle habits are of course crucial, but the enormous influence of certain psychological factors should not be overlooked either: several studies have in fact shown that stress, anxiety, depression and the absence of adequate social relationships exert a negative influence on health and significantly reduce life expectancy.
Among these factors, social isolation is increasingly seen as an important risk factor for premature mortality. For example, a meta-analysis of 148 studies (308,849 people) reported that unsatisfactory social relationships are associated with a 50% increased risk of mortality, compared to people whose social relationships are well developed.
Loneliness: twice the risk of heart attack and stroke
It seems that this decrease in life expectancy observed in socially isolated people is largely due to an increased risk of cardiovascular disease: several studies show that low social support is associated with an increase of approximately twice the risk of cardiovascular events such as myocardial infarction or stroke. The mechanisms involved remain poorly understood, but it is believed that this influence of the social network is mainly due to two factors:
– Social relationships act as “stress buffers” that reduce the negative impacts of various life trials (illness, bereavement and divorce, for example).
Stress is an important risk factor for cardiovascular disease and the support provided by an adequate social network can therefore help to better absorb the shock associated with these events and reduce the harmful physiological consequences that result from chronic stress.
– Studies also show that individuals who have a developed social network tend to be more physically active and adopt better lifestyle habits, which contributes to reducing the risk of cardiovascular disease and improving life expectancy.
Friends, relationships, group activities protect the heart
A study recently published in Circulation Research provides a better understanding of the relative contribution of these two types of factors to the reduction in the risk of cardiovascular disease associated with the social network.
By examining the levels of social integration of 76,362 participants in the Nurses’ Health Study, a team of American researchers observed that women who had the most developed social networks (spouse, large number of friends, regular participation in social or religious activities) had about 50% less risk of being affected by a coronary event (myocardial infarction, sudden cardiac death) than those who were the least well integrated socially.
Further analysis revealed that the adoption of better lifestyle habits by the most socially active women played an important role in this reduction in the risk of cardiovascular events, including a significant reduction in smoking and an increase in levels of physical activity. On the other hand, these lifestyle habits do not fully explain the protection offered by the social network, since the researchers observed that socially isolated women had higher levels of inflammatory markers and were at greater risk of fatal coronary events.
Isolation is experienced as aggression
It is possible that isolation is perceived by the body as a form of “aggression” and causes the activation of physiological mechanisms involved in the stress response, which creates a pro-inflammatory environment and an increased risk of cardiovascular disease. .
The influence of the social network is therefore complex, involving both physical (lifestyle) and psychological factors. But whatever the mechanisms involved, it is certain that a dynamic and diversified social network represents a major asset for a long and healthy life.
Moreover, in all regions of the world recognized for the longevity of their inhabitants (Okinawa, for example), the social fabric is an essential ingredient for a long life, in the same way as healthy eating and regular physical activity.
1 Holt-Lunstad J et al. Social relationships and mortality risk: a meta-analytic review. PLoS Med, 2010; 7: e1000316.
2 Chang SC et al. Social integration and reduced risk of coronary heart disease in women: the role of lifestyle behaviors. Circ Res, 2017; 120: 1927-37.